930
FXUS61 KPHI 230503
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
103 AM EDT WED APR 23 2025
SYNOPSIS
HIGH PRESSURE BUILDS DOWN OUT OF CANADA AND INTO THE MID-ATLANTIC
REGION THROUGH WEDNESDAY. THE HIGH THEN SHIFTS OFFSHORE WEDNESDAY
NIGHT INTO THURSDAY, WITH A WARM FRONT LIFTING NORTHWARD ACROSS
THE AREA FRIDAY NIGHT. A COLD FRONT WILL FOLLOW FOR FRIDAY NIGHT
INTO SATURDAY AS LOW PRESSURE LIFTS TO THE NORTHEAST OUT OF THE
OHIO VALLEY FRIDAY AND INTO NEW ENGLAND THROUGH SATURDAY. HIGH
PRESSURE RETURNS FOR SUNDAY INTO MONDAY.
NEAR TERM /THROUGH TODAY/
NO REAL CHANGES TO THE GRIDS. NUDGED TEMPERATURES UP A FEW
DEGREES, BUT LOWS SHOULD STILL END UP NEAR THE ORIGINAL
FORECAST. OTHERWISE, WE ARE ON TRACK. QUIET NIGHT ONGOING WITH
SOME SHOWERS SKIRTING BY SOUTH OF DELAWARE.
OTHERWISE, HIGH PRESSURE FROM THE GREAT LAKES BUILDS IN TONIGHT
AND KEEPS FAIR WEATHER ACROSS OUR AREA. THE NEW AIRMASS IS SEVERAL
DEGREES COOLER THAT THE PREVIOUS ONE SO LOW TEMPERATURES TONIGHT
ARE FORECAST TO DROP INTO THE 40S TO LOW/MID 50S ACROSS THE
REGION.
WEDNESDAY, A MOSTLY SUNNY SKY IS FORECAST. HIGH TEMPERATURES
WILL RANGE FROM THE UPPER 60S FOR THE POCONOS TO THE MID 70S FOR
METRO PHILADELPHIA AND SOUTHERN NJ. A NORTH TO NORTHEAST WIND
IS EXPECTED AND A SEA BREEZE SHOULD ORGANIZE AND MOVE INLAND
SOME TOWARD LATE MORNING AND IN THE AFTERNOON. THIS SHOULD TURN
THE WINDS TO MORE EAST TO SOUTHERLY ESPECIALLY EAST OF THE SEA
BREEZE FRONT. THE WIND SPEEDS ARE EXPECTED TO BE MUCH LIGHTER
WEDNESDAY HOWEVER COMPARED TO TODAY. HIGHS WILL BE NOTICEABLY
COOLER (50S/60S) ALONG THE COASTAL AREAS WITH AN ONSHORE FLOW
DEVELOPING/STRENGTHENING BY AFTERNOON.
SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/
HIGH PRESSURE WILL BUILD OFFSHORE BEGINNING WEDNESDAY NIGHT AND
REMAIN NEAR THE ARE THROUGH THURSDAY NIGHT. THIS WILL KEEP FAIR
WEATHER IN THE FORECAST THROUGH THURSDAY NIGHT, WITH TEMPERATURES
ABOVE NORMAL.
LONG TERM /FRIDAY THROUGH TUESDAY/
THE HIGH WILL BEGIN TO MOVE OUT TO SEA THROUGH THE DAY FRIDAY,
BEFORE A WARM FRONT LIFTS ACROSS THE AREA LATER FRIDAY INTO
FRIDAY NIGHT. A COUPLE OF SHORT WAVE/VORTICITY IMPULSES MAY MOVE
ACROSS THE AREA DURING THE DAY, WHICH COULD LEAD TO A FEW
SHOWER DURING THE AFTERNOON NORTH OF THE WARM FRONT. BY FRIDAY
NIGHT INTO, A COLD FRONT WILL APPROACH AND MOVE ACROSS THE AREA
AS AN AREA OF LOW PRESSURE MOVES OUT OF THE OHIO VALLEY FRIDAY
NIGHT AND INTO NEW ENGLAND THROUGH SATURDAY. SHOWER CHANCES WILL
INCREASE FRIDAY NIGHT INTO SATURDAY, AND WITH SOME WEAK
INSTABILITY, THERE IS AN ISOLATED CHANCE OF A FEW THUNDERSTORMS.
AS PWS INCREASE TO OVER 1.5 INCHES IN SOME AREAS, SOME PERIOD
OF MODERATE TO HEAVY RAIN WILL BE POSSIBLE. ABOVE NORMAL
TEMPERATURES WILL REMAIN FOR FRIDAY INTO SATURDAY.
THE COLD FRONT PUSHES OFFSHORE SATURDAY NIGHT, BEFORE HIGH
PRESSURE BUILDS INTO THE MID ATLANTIC REGION SUNDAY INTO MONDAY,
BEFORE SHIFTING OFFSHORE MONDAY NIGHT AND OUT TO SEA TUESDAY.
DRY WEATHER WILL RETURN FOR SATURDAY NIGHT THROUGH TUESDAY, AND
AFTER A BRIEF PERIOD OF NEAR NORMAL TEMPERATURES SATURDAY NIGHT
INT SUNDAY, ABOVE NORMAL TEMPERATURES RETURN FOR SUNDAY NIGHT
THROUGH TUESDAY.
AVIATION /05Z WEDNESDAY THROUGH SUNDAY/
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TONIGHT...VFR WITH HIGH CLOUDS. WEST TO NORTHWEST WINDS 5-10 KNOTS,
BECOMING LIGHT AND VARIABLE AT MAY SITES. THE WINDS THEN BECOME
NORTH TO NORTH-NORTHEAST NEAR 5 KNOTS TOWARD DAYBREAK. MODERATE
CONFIDENCE.
WEDNESDAY...VFR. NORTH TO NORTHEAST WINDS 5-10 KNOTS, BECOMING
SOUTHWEST OR SOUTH. A SEA/BAY BREEZE DEVELOPS AND SHOULD SHIFT
THE WINDS TO EAST AND SOUTHEAST AT KACY, KILG AND POSSIBLY MIV.
LOW CONFIDENCE ON WIND DIRECTION DETAILS/TIMING.
WEDNESDAY NIGHT...VFR. WINDS LIGHT AND VARIABLE, POTENTIALLY
FAVORING A SOUTHERLY DIRECTION IF ANYTHING, 5 KT OR LESS. HIGH
CONFIDENCE.
OUTLOOK...
THURSDAY-THURSDAY NIGHT...VFR.
FRIDAY-SATURDAY...SUB VFR CONDITIONS, ESPECIALLY FRIDAY NIGHT
INTO EARLY SATURDAY AS SHOWER CHANCES INCREASE.
SATURDAY NIGHT-SUNDAY...VFR.
MARINE
TRANQUIL CONDITIONS CONTINUE TONIGHT AND WEDNESDAY WITH HIGH
PRESSURE ACROSS THE AREA. THE CONDITIONS ARE EXPECTED TO REMAIN
BELOW SMALL CRAFT ADVISORY CRITERIA. A SEA AND BAY BREEZE
DEVELOPING DURING WEDNESDAY SHOULD RESULT IN AN INCREASE IN THE
WINDS SOME ESPECIALLY NEARSHORE.
OUTLOOK...
WEDNESDAY NIGHT-FRIDAY...CONDITIONS EXPECTED TO REMAIN BELOW
ADVISORY LEVELS.
FRIDAY NIGHT-SUNDAY...WINDS REMAIN BELOW ADVISORY LEVELS,
HOWEVER SEAS MAY APPROACH AND LINGER NEAR 5 FEET THROUGH THE
WEEKEND.
FIRE WEATHER
THE RELATIVE HUMIDITY WILL CONTINUE TO REBOUND TONIGHT AS
TEMPERATURES COOL AND THE WINDS DIMINISH DUE TO LOWERING MIXING
HEIGHTS.
THE RELATIVE HUMIDITY VALUES ARE A TOUCH LOWER FOR MUCH OF THE
AREA WEDNESDAY AND THURSDAY, BUT WINDS WILL BE LIGHTER. SEA/BAY
BREEZES WEDNESDAY SHOULD RESULT IN A RECOVERY OF THE RELATIVE
HUMIDITY TO ITS EAST. RELATIVE HUMIDITY RECOVERS MORE THIS
WEEKEND. GIVEN LIGHTER WINDS, THERE ARE NO FIRE WEATHER CONCERNS
EXPECTED REGARDING RAPID FIRE SPREAD.
PHI WATCHES/WARNINGS/ADVISORIES
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
SYNOPSIS...GORSE/ROBERTSON
NEAR TERM...GORSE/HOEFLICH/OHARA
SHORT TERM...ROBERTSON
LONG TERM...ROBERTSON
AVIATION...GORSE/HOEFLICH/OHARA/ROBERTSON
MARINE...GORSE/OHARA/ROBERTSON
FIRE WEATHER...GORSE/OHARA/ROBERTSON
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